1. Field of the Invention
The invention relates to an electronic circuit comprising a plurality of at least a first transconductor and a second transconductor, each having first and second input terminals for receiving a differential voltage and having first and second output terminals for supplying a differential current in response to the differential voltage.
2. Description of the Related Art
Such an electronic circuit is known from "A Micropower CMOS Continuous-Time Low-Pas filter", IEEE Journal of Solid-State Circuits, Vol. 24, No. 3, June 1989, pp. 736-743. Transconductors are voltage-controlled current sources used in so-termed Transconductor-C filters, also referred to as Balanced Integrator Filters, because the electronic circuits are generally constructed as balanced devices. The background technique for filters of this type is described comprehensively in the book "Integrated Continuous-Time Filters", edited by Y. P. Tsividis and J. O. Voornan, IEEE Press, New York, in which book said IEEE-article appears as Paper 3-B.4. The simplest transconductor is the differential transistor pair. The operational transconductance amplifier (OTA) can be regarded as a complex transconductor. Transconductor-C filters are often integrated, the aim then being, on the one hand, to use a minimal chip area and, on the other hand, to provide a high-quality filter. Said book discloses many variants and improvements based on the differential pair, with the purpose of improving certain characteristics such as linearity, bandwidth and output voltage swing. This means that there is a need for compact transconductors, i.e. occupying a small chip area, which are suitable for use in transconductor-C filters.